Wiki contributions by "peripheral domain experts" are accounted for almost 80% as some report said but it is true for every blog as well most of content comes from private source who shares their expertise or opinion.

Aaron Swartz did some initial research comparing Wikipedia contributors by number of edits and characters, arguing that the core community (who make most of the edits) should matter less than peripheral domain experts (who write more). He is running for the Wikimedia Foundation's board as a pro...